Research Progress of Hyperspectral Imaging Technology in Biological Evidence / 法医学杂志

Hyperspectral imaging technology can obtain the spatial and spectral three-dimensional imaging of substances simultaneously, and obtain the unique continuous characteristic spectrum of substances in a wide spectrum range at a certain spatial resolution, which has outstanding advantages in the fine classification and identification of biological substances. With the development of hyperspectral imaging technology, a large amount of data has been accumulated in the exploration of data acquisition, image processing and material inspection. As a new technology means, hyperspectral imaging technology has its unique advantages and wide application prospects. It can be combined with the common biological physical evidence of blood (stains), saliva, semen, sweat, hair, nails, bones, etc., to achieve rapid separation, inspection and identification of substances. This paper introduces the basic theory of hyperspectral imaging technology and its application in common biological evidence examination research and analyzes the feasibility and development of biological evidence testing and identification, in order to provide a theoretical basis for the development of new technology and promote hyperspectral imaging technology in related biological examination, to better serve the forensic practice.

Determination of Bloodstain Age by UV Visible Integrating Sphere Reflection Spectrum / 法医学杂志

OBJECTIVES@#To establish a method for rapid identification of bloodstain age.@*METHODS@#Under laboratory conditions （20 ℃, 25 ℃ and 30 ℃）, an integrating sphere ISR-240A was used as a reflection accessory on an UV-2450 UV-vis spectrophotometer, and a standard white board of BaSO₄ was used as reference, the reflection spectrums of bloodstain from human ears' venous blood were measured at regular intervals. The reflection radios R₅₄₁ and R₅₇₇ at a specific wavelength were collected and the value of R₅₄₁/R₅₇₇ was calculated. The linear fitting and regression analysis were done by SPSS 17.0.@*RESULTS@#The results of regression analysis showed that R² of the ratios of bloodstain age to UV visible reflectivity in specific wavelengths were larger than 0.8 within 8 hours and under certain circumstances. The regression equation was established. The bloodstain age had significant correlation with the value of R₅₄₁/R₅₇₇.@*CONCLUSIONS@#The method of inspection is simple, rapid and nondestructive with a good reliability, and can be used to identify the bloodstain age within 8 hours elapsed-time standards under laboratory conditions.

Determination of Bloodstain Age by UV Visible Integrating Sphere Reflection Spectrum / 法医学杂志

ObjectiveTo establish a method for rapid identification of bloodstain age.MethodsUnder laboratory conditions(20 ℃, 25 ℃and 30 ℃), an integrating sphere ISR-240A was used as a reflection accessory on an UV-2450 UV-vis spectrophotometer, and a standard white board of BaSO4 was used as reference, the reflection spectrums of bloodstain from human ears’venous blood were measured at regu-lar intervals. The reflection radiosR541 andR577 at a specific wavelength were collected and the value of R541/R577 was calculated. The linear fitting and regression analysis were done by SPSS 17.0.ResultsThe results of regression analysis showed thatR2 of the ratios of bloodstain age to UV visible reflectivity in specific wavelengths were larger than 0.8 within 8 hours and under certain circumstances. The regression equation was established. The bloodstain age had significant correlation with the value ofR541/R577.Con-clusionThe method of inspection is simple, rapid and nondestructive with a good reliability, and can be used to identify the bloodstain age within 8 hours elapsed-time standards under laboratory conditions.

Effect of ageing & environmental condition for detection of blood group from blood stain.

It is an established fact that laboratory investigations involving biological fluids play a vital role in crime investigations Blood as a source of evidence associated with crime, can provide valuable information that may solve the case. Proper collection, preservation and dispatch of this crucial evidence to the Forensic Science Laboratory is hence very essential. Improper collection and preservation can weaken or destroy a potential source of facts in a case. Many times the suspects may hide valuable blood stain evidence either on the object or the clothes in different conditions which may adversely affect the investigation. Hence, proper collection and preservation of blood stain is of paramount importance, as it may provide a strong link between an individual and a criminal act. The present study was undertaken to find out the maximum duration for which blood grouping is possible when the stains are exposed to varied environmental conditions.

The detection of blood group in small amount blood stain by microtechnique.

A microtechnique adapted from mixed agglutination method was modified in order to detect blood group in small amount of blood stain (approx 10 microgram). By improving the blood stain solvent and method, the ABO grouping of human blood stain in small amount can be detected correctly almost 100% at the duration of 1 month for blood stain in room temperature and 2 weeks for blood stain under influence of sunlight. The technique was described and show that it is possible to be a routine laboratory examination in forensic medicine.

THE APPLICATION OF DNA AMPLIFICATION TECHNIQUE IN VITRO IN FORENSIC MEDICNE PRACTICE / 中国法医学杂志

This paper reports the determination of sex of human blood stains in threecriminal cases by the DNA amplification technique.The results fit the cases de-tails and gave the scientific evidence for the justice.The blood stains were dige-sted with proteinase K.The protein was extracted with the phenol-chloroform.The DNA was precipitated with NaCl and ethyl alcohol.Amplification of DNAwas carried out using two pairs of primer Y1.1 Y1.2 and Alu9.1 Alug.2 and heatstable FD polymerase.The amplified products were subjected to agarose gel(con-taining ethidium bromide)electrophoresis.Sex of blood stains was determinedaccording to the amplified products.PCR technique is rapid to perform,sensitiveand simple.No special equipments and isotope labelled probe are required.